Handling steel

Handling Steel Plates for Fabrication, Industrial Data Sheet, National Safety Council, Itasca, IL... 

Pipelines are cleaned and inspected using pigs . Pigs usually have a steel body fitted with rubber cups and brushes or scrapers to remove wax and rust deposits on the pipe wall, as the pig is pumped along the pipe. Sometimes spherical pigs are used for product separation or controlling liquid hold up. In field lines handling untreated crude may have to be insulated to prevent wax formation. 

Cryogenics We use several types of evacuated stainless steel cryostats of about 1 htre capacity to provide the 77 K cooling with hquid nitrogen. The simplest, best valued and easiest to handle one is a ordinary thermos flask available from the supermarket (see fig.3). It is sufficient for a measurement period of more than 12 hours. A specially designed stainless steel vessel gains cooling periods of 30 hours. 

Spatulas. Stainless steel, nickel and porcelain spatulas are available commercially. Some of these are shown in Fig. 11,1, 9 (a) is a spatula with a flexible stainless steel blade and is provided with a wooden handle (6) is a nickel spatula and has a tumed-up end to facilitate the handling... 

It is reported that mild carbon steels may be effectively protected by as little as 55 ppm of KTc04 in aerated distilled water at temperatures up to 250oC. This corrosion protection is limited to closed systems, since technetium is radioative and must be confined. 9sTc has a specific activity of 6.2 X lOs Bq/g. Activity of this level must not be allowed to spread. 99Tc is a contamination hazard and should be handled in a glove box. 

Commercial acetaldehyde has the following typical specifications assay, 99% min color, water-white acidity, 0.5% max (acetic acid) specific gravity, 0.790 at 20°C bp, 20.8°C at 101.3 kPa (1 atm). It is shipped in steel dmms and tank cars bearing the ICC red label. In the Hquid state, it is noncorrosive to most metals however, acetaldehyde oxidizes readily, particularly in the vapor state, to acetic acid. Precautions to be observed in the handling of acetaldehyde have been pubHshed (103). 

Mild steel is a suitable material of constmction for storage and handling of DMAC at ambient temperatures. Aluminum or stainless steel is recommended for cases involving very stringent color or iron contamination requirements. Mild steel is not recommended for high temperature service or handling aqueous solutions of less than 50 mol % (82.86 wt %) DMAC. 

Shipment, Stora.ge, ndPrice. Butyrolactone is shipped in unlined steel tank cars and plain steel dmms. Plain steel, stainless steel, aluminum, and nickel are suitable for storage and handling mbber, phenoHcs, and epoxy resins are not suitable. Butyrolactone is hygroscopic and should be protected from moisture. Because of its low free2ing point (—44° C), no provision for heating storage vessels is needed. 

Dry chlorine has a great affinity for absorbing moisture, and wet chlorine is extremely corrosive, attacking most common materials except HasteUoy C, titanium, and tantalum. These metals are protected from attack by the acids formed by chlorine hydrolysis because of surface oxide films on the metal. Tantalum is the preferred constmction material for service with wet and dry chlorine. Wet chlorine gas is handled under pressure using fiberglass-reinforced plastics. Rubber-lined steel is suitable for wet chlorine gas handling up to 100°C. At low pressures and low temperatures PVC, chlorinated PVC, and reinforced polyester resins are also used. Polytetrafluoroethylene (PTFE), poly(vinyhdene fluoride) (PVDE), and... 

Steel is an acceptable material of constmction for handling solutions of up to 50% NaOH below 40°C. Above 40°C the steel corrosion rate increases rapidly and iron is picked up in the solution. Materials for handling 50% NaOH are lined steel for tank cars and lined or unlined steel for tanks and piping. 

Fluorine can be handled using a variety of materials (100—103). Table 4 shows the corrosion rates of some of these as a function of temperature. System cleanliness and passivation ate critical to success. Materials such as nickel, Monel, aluminum, magnesium, copper, brass, stainless steel, and carbon steel ate commonly used. Mote information is available in the Hterature (20,104). 

Because hydrogen fluoride is extremely reactive, special materials are necessary for its handling and storage. Glass reacts with HF to produce SiF which leads to pressure buildup and potential mptures. Anhydrous hydrogen fluoride is produced and stored ia mild steel equipment. Teflon or polyethylene are frequently used for aqueous solutions. 

Aqueous hydrogen fluoride of greater than 60% maybe handled in steel up to 38°C, provided velocities are kept low (<0.3 m/s) and iron pickup in the process stream is acceptable. Otherwise, mbber or polytetrafluoroethylene (PTFE) linings are used. For all appHcations, PTFE or PTEE-lined materials are suitable up to the maximum use temperature of 200°C. PTEE is also the material of choice for gasketing. AHoy 20 or Monel is typically used for valve and pump appHcations. Materials unacceptable for use in HE include cast iron, type 400 stainless steel, hardened steels, titanium, glass, and siHcate ceramics. 

Handling and Safety Factors. Oxygen difluoride can be handled easily and safely in glass and in common metals such as stainless steel, copper, aluminum. Monel, and nickel, from cryogenic temperatures to 200°C (4). At higher temperatures only nickel and Monel are recommended. The compatibihty of OF2 with process equipment depends largely on the cleanliness of the equipment contaminants such as dkt, moisture, oil, grease, scale... 

Induction heating equipment installations can require significant investment in electric power components as well as the work handling equipment made necessary by the process. These costs can be offset by savings in plant space, reduction in metal loss, precise control of product temperature, and reduced in-process inventory. A typical continuous induction heating line consumes about 360 kW h/t heating carbon steel bars to 1230°C. 

Handling Temperatures. Optimum temperature for pumping is in 37—48°C range. Piping should be stainless steel, aluminum, or galvanized iron. Valves and pumps should be bronze, cast-iron with bronze trim, or stainless steel. A pump of 3.15-L/s (50-gal/min) capacity unloads a tank car of warm glycerol in ca 4 h. 

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